It's kind of amazing to look back over J.K. Rowling's "Harry Potter" book series.

The first book, "Harry Potter and the Sorcerer's Stone," arrived in the United States at the end of 1998. Three years later, director Chris Columbus' movie adaptation hit theaters. Perhaps more than anything else, fans delighted in seeing their favorite characters from the book series — then on its fourth entry, "Goblet of Fire" — brought to life by a group of perfectly cast actors, led by Daniel Radcliffe's Harry.

Now in 2009, we're coming into the home stretch for the movies. The final book reached readers in summer 2007, just a week after the film adaptation of book five, "Order of the Phoenix," hit theaters. Director David Yates' adaptation of "Half-Blood Prince," the sixth and penultimate book, hits theaters Wednesday (July 15), and our MTV Cheat Sheet is here to help bring you up to speed on what's been happening at Hogwarts.

Growing Pains

One of the most incredible elements to the "Harry Potter" movie series has been watching the three main castmembers — Daniel Radcliffe, Rupert Grint and Emma Watson — grow up. Not grow as actors, mind you, but literally age from children into adults.

For years now, we've seen their slow, often graceless (adorably so) shift into puberty. Early glimmerings of romance marked the previous outing. They return in full force for "Half-Blood Prince," as Harry pairs up with Ginny Weasley (Bonnie Wright), and Ron, after some fumbling ignorance, embraces his long-foreshadowed connection with Hermione.

It must be strange for these kids, though. After all, they've been behaving like schoolchildren together on the "Harry Potter" sets since the dawn of the millennium. Watson and Grint were particularly uncomfortable sharing that first kiss in "Prince." As for Radcliffe, he claims to have had some trouble in real life meeting women on the "Potter" sets since he's always dressed like a schoolboy.

Sibling Rivalry

Before there was "Twilight," there was "Harry Potter." And before Edward Cullen, there was Cedric Diggory, two characters brought to life by Robert Pattinson. In comparison to "Potter," "Twilight" is still a movie franchise in its infancy. Even still, the teen-vampire story has blown up almost overnight as a cultural touchstone.

How have the "Potter" stars reacted to Pattinson's dynamite success as a de-fanged vampire? Radcliffe apparently hates Pattinson. OK, that's not true at all. He's actually delighted by the success of his former castmate, although the two haven't spoken in years and Radcliffe hasn't yet seen "Twilight." Watson is similarly impressed. She accepts that no one saw "Twilight" exploding as big or as quickly as it did, but she always figured that her "Order of the Phoenix" pal had a bright career ahead of him.

Taking Center Stage

So far in the "Harry Potter" movies, the characters of Ginny Weasley and Draco Malfoy (Tom Felton) have kept mostly to the sidelines. Sure, Ginny did have a more central role in "Phoenix," and Malfoy has been Potter's schoolhouse nemesis since day one. Still, the two characters are vitally important to the overall arc of the story, and it can be argued that "Half-Blood Prince" is when they really come into their own.

Wright particularly enjoyed seeing her character grow up in "Prince." There's a scene in which she steps out onto the Quidditch pitch with Harry, the team captain. Frustrated by Harry's unsuccessful attempts to catch the attention of the gathered tryouts crowd, Ginny steps up and demands order. Wright enjoyed this scene in particular and the good it did for establishing her character as a sort of willful tomboy.

Felton, on the other hand, has fully embraced his character's pivotally evil role in the series. He appreciates that certain features are key in establishing a villain as iconic, which is how he views Draco: the cold eyes, the pasty face, the affectation or standout feature (i.e. Bond villain Blofeld's cat). For those who haven't read the books, it now remains to be seen how Ginny and Draco will influence the climactic final chapter.